Tutorial COMMISSIONING AND ACCEPTANCE Corrado Rocca 1
Introduction TUTORIAL OUTLINE The Acceptance process within the contractual Plan of Work The Acceptance periods From Product Design acceptance to System Final Acceptance The power budget Relevant measurement set-ups, results and data in the acceptance period Questions and discussion 2
INTRODUCTION 3
TECHNICAL SPECIFICATIONS Tenders and Supply Contracts for Submarine Cable Systems or Networks always contain a part called Technical Specifications The Technical Specifications define the technical requirements, Scope of Work, performance parameters and Acceptance of a System 4
SOME DEFINITIONS Acceptance means the activities, including but not limited to, procedures, tests and approvals necessary to show that all the defined parameters, facilities and requirements given in the Acceptance Chapter of the Technical Specifications of this Contract have been met to demonstrate confidence in the continuous satisfactory operation of the System throughout its Design Life (definition from recent submarine tenders).. Therefore the Commissioning is only a part of the Acceptance of a submarine system!!! 5
SUBMARINE REPEATERED SYSTEM This tutorial will discuss the Acceptance of submarine repeatered systems 6
TYPICAL CONTRACTUAL REQUIREMENTS FOR SYSTEM ACCEPTANCE 7
THE PLAN OF WORK The contractual Plan Of Work defines all the steps that have to be implemented for the successful completion of a System, including its Acceptance 8
THE ACCEPTANCE PROCESS The typical Acceptance process is divided into Acceptance Periods In each period, the Supplier (or Contractor) has to submit all the necessary documentation, test procedures and test results to the Purchasers for approval. Such documentation is gathered in the System Acceptance Handbook Typically all tests are performed under the Contractor s responsibility The Purchasers can opt to follow the Acceptance process themselves or to second the task to a competent inspector (typically belonging to a national PTT or telecom authority) Most periods are linked to a Billing Milestone and consequent payment after successful verification 9
THE MAIN ACCEPTANCE PERIODS I. Product design acceptance II. III. IV. Factory Acceptance Testing (FAT) Wet plant assembly acceptance System Loading and Laying (SLL) testing V. Site Acceptance Testing (SAT) VI. VII. VIII. System (end-to-end transmission) testing System confidence trial and Provisional Acceptance System Final Acceptance 10
PRODUCT DESIGN ACCEPTANCE I. Product maturity and qualification status evaluation II. III. IV. Technical explanation of assumptions under the contractual power budget Technology demonstration, proving transmission capability with final capacity and inter-operation with SIE Possible multi-vendor products integration verification TX R1 R2 R3 R4 SMR G G G G α α α α α Ri+1 Ri Ri-1 GFU G G G TEU α α α α SMR RN-3 RN-2 RN-1 RN G G G G α α α α α RX 11
TECHNOLOGY DEMONSTRATION 12
FACTORY ACCEPTANCE TESTS (FAT) The purpose is to confirm that the products are compliant with the Technical Specifications and will meet the System requirements Tests are carried out on the basis of a FAT procedure I. Dry Plant Equipment acceptance II. I. Submarine Line Terminating Equipment II. Power Feeding Equipment Wet Plant Equipment acceptance I. Cable (each span) II. III. IV. Repeaters Branching Units Equalizers Purchasers may decide not to follow all the tests; in any case factory test reports have to be checked and approved 13
WET PLANT ASSEMBLY ACCEPTANCE The purpose is to confirm that the assembled wet plant will meet the System requirements They typically comprise» OSNR / pre-emphasis tests» Chromatic Dispersion tests» Voltage / Current tests (V/I characterization)» Supervisory tests» BER tests (when applicable) Depending on loading/laying strategies and segment lengths, tests may be carried out on loading/laying blocks, therefore the acceptance criteria are scaled accordingly It is important to remind that during the repeater to cable assembly, each operation is carefully monitored, through splices verification (via splicing machine or active supervision) and through insulation tests 14
DISPERSION MAP TEST RESULTS Cumulative Chromatic Dispersion @ 1551.5 nm (2 C) 1500 Fiber 1 1000 Fiber 2 Min Chromatic Dispersion ps/nm 500 0-500 Max 0 200 400 600 800 1000 1200-1000 -1500 Segment Length [km] 15
LOADING AND LAYING TESTS The purpose is to confirm that during operations the assembled cable performance is not impaired They typically comprise» OSNR tests» Voltage / Current tests» Supervisory tests» Branching Units tests (when present) Depending on loading/laying strategies and segment lengths, tests may be carried out on loading/laying blocks, therefore the acceptance criteria are scaled accordingly 16
SITE ACCEPTANCE TESTS (SAT) These tests are carried out after terminal station installation to verify that the Dry Plant equipment is installed and performs properly They typically comprise a selected subset of FAT procedures» OSNR launched from SLTE» Back-to-back error tests on SLTE (BER vs. OSNR curve)» PFE performance and tests on dummy load» Local software monitoring tests through LCT or EMS» SIE tests (if within the SOW)» Land cable and return earth tests They are performed first at equipment level (Suite tests), then on spares and finally at station level (Station Integration tests) The contractual Plan Of Work typically foresees Contractor s SAT tests and, if requested, also Purchasers SAT tests 17
END-TO TO-END / COMMISSIONING TESTS These tests are carried out after the lay and the final splice (terrestrial to wet cable joint) execution and the set-up of the complete end-to-end Segment or System They typically comprise» Transmission tests (OSNR, BER based Q-factor and commissioning margins)» Final capacity demonstration» Wet Plant Supervisory tests (repeaters monitoring and C-OTDR)» System powering tests» Software tests (DCN tests, NE remotization, alarm generation and detection, performance monitoring)» System interfaces, synchronization, protection, maintenance and restoration tests The contractual Plan Of Work typically foresees Contractor s tests and, if requested, also Purchasers tests 18
THE POWER BUDGET Parameter BOL Q in db 1 Mean Q value (from simple SNR calculation) 21.0 18.5 1.1 Propagation impairments due to combined effects of chromatic dispersion, nonlinear effect, four-wave mixing effects, stimulated Raman scattering effects, etc. 1.5 1.5 1.2 Gain flatness impairments 0.5 0.5 1.3 Non-optimal optical pre-emphasis impairment 0.25 0.25 1.4 Wavelength tolerance impairment 0.2 0.2 EOL Q in db 1.5 Mean PDL penalty <0.1 <0.1 1.6 Mean PDG penalty <0.1 <0.1 1.7 Mean PMD penalty <0.1 <0.1 1.8 Supe rvisory impairment.5 0.5 1.9 Manufacturing and environmental impairment 1 1 2 Time varying system performance (5 sigma rule) 1.2 1.2 3 Line Q value (1-1.1 to 1.9-2) 15.85 13.35 4 Specified TTE Q value (back to back) 22.0 20.0 5 Transmission Segment Q value (computed from 3 and 4) 14.91 12.5 5.1 BER corresponding to segment Q without FEC 1.4e-8 1.3e-5 5.2 BER corresponding to segment Q with FEC <1e-13 <1e-13 5.3 Effective Transmission Segment Q value with FEC >17 >17 6 Q limit compliance with G.826 after FEC correction 11.3 11.3 7 Repairs margins Components and fibre ageing penalty Pump(s) failure penalty Non-optimal decision threshold - 2.5 8 Segment Margins 2.20 1.0 9 Unallocated supplier margin 1.41 0.2 10 Commissioning limits 13.5 Commissioning limit SOL conditions EOL conditions FEC capability 19
TRANSMISSION TESTS SIE IN O E TX- FEC TX-S-LINE E O RX-S-LINE O E RX-FEC TO SIE E O STM-64 10.66 Gb/s 10.66 Gb/s STM-64 O E TO SIE RX-FEC E O RX-S-LINE WDM MUX/DeMUX SUBMERGED LINE WDM MUX/DeMUX O E TX-S-LINE TX -FEC O E SIE IN LINE (Line 3) TRANSMISSION SEGMENT (Lines 5 & 5.1) Effective TRANSMISSION SEGMENT (Lines 5.2 & 5.3) 20
TRANSMISSION TEST RESULT 1.00E-03 1.00E-04 1.00E-05 1.00E-06 Commissioning Limit Back-to-Back With Line @ SOL 1.00E-07 BER 1.00E-08 1.00E-09 1.00E-10 SOL OSNR 1.00E-11 OSNR MARGIN 1.00E-12 10.00 11.00 12.00 13.00 14.00 15.00 16.00 17.00 18.00 19.00 OSNR [db] 21
FULL CAPACITY TESTING The Contractor must prove to Purchasers System operation and power budget margins at the committed final capacity, although initially the System is typically lit with few wavelengths Several methods are possible; a practical set up employs the equipped transponders together with dummy channels, as described in the paper Optical test equipment for performance evaluation of installed DWDM systems - OFC2002, TuY3 The system is loaded with dummy signals through which the equipped transponders powers are set at levels equivalent to full capacity conditions. Few of these dummy channels (typically 4 or 6) are narrowly spaced across the tributary under test in order to induce non-linear penalties 22
FULL CAPACITY TEST SET-UP Equipped Transponders FROM LINE TO LINE RECEIVE AMPLIFIER TRANSMIT AMPLIFIER OPTICAL MULTIPLEXER LINE OUT LINE IN LINE OUT LINE IN LINE OUT LINE IN LINE OUT LINE IN CLIENT IN CLIENT OUT CLIENT IN CLIENT OUT CLIENT IN CLIENT OUT CLIENT IN CLIENT OUT Amplifier OPTICAL ATTENUATOR OPTICAL ATTENUATOR External Modulator Amplifier PM Coupler DW L DW DWL DW L DWL DW DWL DWL L DWL DW DWL DWL L DWL DW L DWL L DW L DW L DW L DW L DW L OSA Transmit Monitor Port Output Transmit Port Input 23
WET PLANT SUPERVISION Loopback Supervisory method Span_A 1 Span_A N SLTE HLLB0 G_A 0 G_A N Span_B 1 HLLB1 Span_B N HLLBN Far-end HLLB Far End SLTE G_B 0 G_B N SPAN 1 R1 Faulty repeater RN SPAN N SPV Signal Loop Back Path Loop_Gain(N) = N N 1 G_Ai + G_Bi Span_Ai i= 0 i= 0 i= 1 i= 1 N N Span_B i HLLB N 24
WET PLANT SUPERVISION Active Supervision method SPV Interrogation SPV Response Span_A 1 Span_A N SLTE G_A0 Span_B 1 R1 Span_B N G_AN RN Far End SLTE G_B0 G_BN SPAN 1 Addressed repeater SPAN N 25
WET PLANT SUPERVISION Coherent OTDR 0-5 First span not visible Submarine Amplifier Span Length Amplitude (db) -10-15 -20-25 PEU Span Loss -30-35 Far End Terminal Station -40 0 100 200 300 400 500 600 Distance (Km) 26
SYSTEM POWERING TESTS System Power up System Power down V/I Characterisation BU configuration System performance with different powering scenarios Single End Feeding Double End Feeding PFE fault Converter fault Electroding 27
SW AND DCN TESTS Station C Station A To Land network / NOC To Land network Router EMS Router EMS LAN HUB LCT NEs Station B LAN HUB NEs WAN LAN Other Interfaces User channels User channels WAN connectivity via FEC Overhead Channels DCN tests verify the connectivity among the different terminal stations LANs and the remotization of far-end Network Elements Alarm tests verify proper alarm generation and clearance of induced faulty conditions Performance Monitoring tests verify correct management of ITU-T G.826 parameters: EB, BBE, ES, SES, UAS recorded at intervals of 15 minutes and 24 hours. 28
OTHER TESTS System interfaces SIE interfaces (power levels, jitter, eye-diagrams, AIS generation etc) User channels EMS interfaces (North-bound, when applicable) Synchronization distribution over the whole System Protection mechanisms verification Equipment redundancies 1+1 linear protection 1:N tributary protection Ring protection Exercising of maintenance procedures Traffic provisioning and management Network Elements configuration Restoration criteria Collection of maintenance and baseline data 29
SYSTEM CONFIDENCE TRIAL The Continuous Confidence Trial aims at demonstrating that the installed system operates error-free over a long term test period (typically 2 weeks) A daily log through the OMC monitors the absence of irregularities, variations, alarms and non-routine events For systems employing Forward Error Correction (FEC), the recording of the pre-fec BER allows measuring the system margins for each equipped Digital Line Section Using pre-fec performance parameters recorded at 15-min intervals it is possible to derive the statistics of the error occurrences and to prove with a certain confidence level (above 95%) the PB Commissioning Limit 30
SYSTEM PROVISIONAL ACCEPTANCE The Provisional Acceptance Certificate is issued by the Purchasers provided that The results of the Acceptance Test Program included in the Acceptance Handbook indicate compliance of the System throughout its Design Life with the requirements of the Technical Specification The Contractor has provided all the deliverables required by the Contract (including documentation, spares, training etc) During the Confidence Trial nothing has developed that is likely to cause the System to fail to meet the requirements of the Technical Specification With the PAC issuance the Purchasers officially accept the System, the implementation activities are concluded and the Warranty Period begins 31
SYSTEM FINAL ACCEPTANCE At the end of the Warranty Period a Final Acceptance Certificate is issued by the Purchasers provided that The OMC data gathered after the Provisional Acceptance date confirm long-term transmission quality performance No Pattern of Failure or Degradation has developed that is likely to cause the System to fail to meet the requirements of the Technical Specifications The performed Final Acceptance Tests indicate compliance with the Technical Specifications With the FAC issuance the Warranty Period is concluded, the Performance Bond is released and the out-of-warranty period begins 32
33